Engineering Research Equipment Grant: Instruments for Observation of Microtremors in the Los Angeles Basin

为抗震结构的设计制定可靠的设计程序，需要了解结构场地周围的土壤材料对地震荷载的响应方式。然而，由于地震的罕见性质，以及不同地点土壤的地质和物理性质的差异，几乎不可能提供每个拟议地点的此类记录。这一行动是为了提供设备来测量整个洛杉矶盆地的长周期微震。微震，或微地震，是由自然事件产生的地球的微小震动或振动，如海浪冲击海岸或道路交通。它们与地震无关，但可以用来更好地了解地震引起的地面震动过程，正如这里所建议的那样。洛杉矶盆地测得的微震将与该盆地现有的强地面运动测量结果进行比较。之前对日本微震数据的研究强烈表明，微震数据可以用来了解特定地点对破坏性地震的强烈运动反应。首席调查人员因其在地震工程研究方面的专业知识而受到认可，并拥有有效使用将要购买的设备的机构资源。

The development of reliable design procedures for the design of earthquake resistant structures requires an understanding of the manner in which the surrounding earth material at the site of a structure responds to seismic loading. However, due to the infrequent nature of earthquakes, and to the variability in the geology and physical properties of the soil at different locations, it is virtually impossible to provide such records for every proposed site. This action is to provide equipment to measure the long period microtremors in the entire Los Angeles basin. Microtremors, or microseisms, are small tremors or vibrations of the earth that are generated by natural occurrences such as the pounding of surf on the shore, or road traffic. They are not associated with earthquakes, but may be used, as is proposed here, to understand better the process of ground shaking due to earthquakes. The measured microtremors in the Los Angeles basin will be compared with existing strong ground motion measurements in the basin. Previous studies of microtremor data in Japan strongly suggests that microtremor data can be used to understand the strong motion response at a particular site to a damaging earthquake. The principal investigators are recognized for their expertise in earthquake engineering studies, and have the institutional resources to use effectively the equipment to be purchased.